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@uiten tutr 'gstmt @Hirn CHARLES H. A-MIDON, 0F GREENFIELD,MASSACHUSETTS.

Leners Paten; No. 64,931, ma May 21, 1867.

IMPROVEMENT IN BRAGES FOB. BITS.

'IOALL WHOM IT MAY CONCERN:

Be itiknown that I, CHARLES H. AMIDoN,'of Greenfield, in the county ofFranklin, and State of Massachu. setts, have invented a new and usefulImprovement in Bit-Braces; and I do hereby declare the following to be afull, clear, and exact description ofthe same, reference being had tothe accompanying drawings, in which- Figure 1 is a side elevation ofthis invention.

Figure 2 is a front view of the socket.

Figure 3 is an elevation of the clamping device. v

Figure 4 is a perspective view of the socket with clamping device inposition. j v

The object of my invention is to produce a bit-brace with a socket forthe shank of a bit, soconstructed that said shank may be insertedbeneath a clampingstirrup, and not only prevented from turning Withinsaid stirrup and socket, but by a shoulder projecting in front of theshoulder of the shank, the same may be prevented from slipping out ofthe socket.

That others may understand the construction and operation of myinvention, I will particularly describe it.

A is the shank of the brace in which is formed the half-socket D. Theform of the shank A is clearly shown in fig. I. The half-socket D is atapering groove formed in the flat-surface of the shank A, itsre-entrant angle being a right angle, and its taper being such as willcorrespond to the general taper of bit-Shanks. Through .the shank A,transverse to the half-socket D, is a deep recess, b, shown in fig. 2,the centre of whichl penetrates entirely through the shank. Within thisrecess is placed the stirrup B, which is constructed with a rectangularorifice E penetrating through it transversely, the angle F being madeaccurately a right angle. This stirrup is also provided with ascrew-shank, II, 'which projects through the orifice at the bottom ofthe recess b, and upon whichthe thumb-nut C is placed. At the larger-endof the half-socket is a small projecting shoulder, G, placed directly inthe angle to prevent the shank of a bit, when once placed in thehalf-socket D and clamped there, from being pulled out and detached, asthis shoulder then lies directly in. front of the shoulder at one cornerof the shank.

The operation of this device is very simple and perfectly eiective,while in construction is very cheap and unlikely to be deranged. Thethumb-nut C being loosened or run back upon the shank H, permits thestirrup B to be raised out of the recess b, and expose Imore or less ofthe orice E. A bit-shank of any size (within -the capacity of theimplementj'm'ay be introduced through the orifice E, and placed inposition Within the half- 'socket D, the sides of which being at rightangles to each other fit two of the sides ofthe socket. The bit-shankmust be introduced far enough to bring the shoulder in front of itsshank behind the shoulder G and in contact with it. When the bit-shankis in this position the sides of the half-socket D, in contact with twoof the sides vof the bit-shank, the two sides of the orifice E whichjoin ait-F will embrace the two opposite sides of the same shank, and asthe thumb-nut C is screweddown upon the 4vshank H, the bit-shank will bedrawn tight against .the sides of the half-socket D, and rmly heldwhilethe bit is'being rotated' by the brace, and the shoulder G willell'ectually prevent the withdrawal of the bit in the line of its axiswithout loosening the stirrup.

Having described my invention, what I claim as new, and desire to secureby Letters Patent, is- Thecombination of the clamping-stirrup B andshoulder G in the shank of a bit-brace,for the purpose set forth.

CHARLES I-I. AMIDON. Witnesses: v

AUSTIN DnWonr, LEVI J. GUNN.

